The Triglyceride/Fatty Acid CycleS and the role of Glyceroneogenesis

Thanks to a certain journalist, much of the discussion of fat tissue metabolism on the internet presents a very myopic view of things taken out of context.  One example of this, is that in Chapter 22 of GCBC, Taubes lists all of the hormones acting on adipocytes.  The caption on the graphic reads:

In 1965, hormonal regulation of adipose tissue looked like this: at least eight hormones that worked to release fat from the adipose tissue and one, insulin, that worked to put it there.

Let's leave aside for a moment that in the four subsequent decades preceding the writing and publication of his book, probably the most potent regulatory hormone of fat mass, leptin, was discovered.  Let's also leave aside all of the other adipokines (the term for the collection of hormones and peptides produced by adipocytes most of which appear to be secreted).   There's a lesson to be learned solely from Taubes' narrow, outdated view.  Under the title "Hormones that promote fat mobilization", Taubes lists:   Epinephrine, Norepinephrine, Adrenocorticotropic hormone (ACTH), Glucagon, Thyroid-stimulating hormone, Melanocyte-stimulating hormone, Vasopressin, and Growth hormone.  In the opposing column under the title "Hormones that promote fat accumulation", he lists only one:  Insulin.  He precedes this with what he seems think is information either unbeknownst to or forgotten by researchers in the field -- that fatty acids are continually cycling in and out of fat tissue, and that caloric excess is not required for deposition, nor is caloric deficit required for mobilization.

Read more »